Wireless sensor networks are being applied to agriculture and natural resource management. An example of a wireless network used in an agricultural application is disclosed in U.S. Patent Application Publication No. 2007/0039745 A1 (Anderson et al.), which is assigned to the Assignee of the present invention. A wireless network of this type typically includes a plurality of sensor nodes, with each sensor node having a printed circuit board connected to a battery. The circuit board and battery are typically placed within a housing. For certain applications, it may not be possible or economically feasible to retrieve the sensor nodes after the battery is depleted. Printed circuit boards used in conventional sensor nodes contain lead solder and are considered hazardous waste. Batteries may also contain environmentally unfriendly chemicals and/or materials. Thus, the widespread use of existing sensor nodes can lead to environmental damage over years of use.